To use Clonezilla, you need to download Clonezilla Live first, and burn it to CD, then boot the computer from the CD. At the first step, just click Enter. Then, you can follow the guide to select language; choose the way your keyboard is laid out.What version of Clonezilla Live should I use?
All versions of Clonezilla live support machine with legacy BIOS. If your machine comes with uEFI secure boot enabled, you have to use AMD64 (X86-64) version (either Debian-based or Ubuntu-based) of Clonezilla live.